[XLR99]

For a 5pt bonus, name the reg that applies to this question.
Above and beyond the briefing, go out of your way to fly smoothly, use shallow bank angles, be smooth on the power transitions, etc. Don't be like the tools in the 172 vomit comet video a few months ago with the chicks puking all over the airplane. Non pilots generally think they are going to die if you bank over about 15deg., or if anything unexpected happens.
Since you mention Cherokee, make sure you get the door to minimize the chance of it popping; also has double benefit if your pax is hot....